I was looking for an explanation of exactly how a one-point safety is possible in football, and didn't find one. Therefore, I went to the font of all things football, the NFL rule book. (May be harder to read than the baseball rule book, not recommended reading).

Much like Brad Nessler in 2004 during the previous one-point safety (between Texas and Texas A&M), I thought a point-after try could only end in one or two points for the offense, and any possession by the defense would result in a dead ball. This is indeed the rule in the NFL. In the NFL, a one-point safety can be awarded only when the defense "muffs" the ball on its way out of the back of the end zone, and so it has not happened in the modern era.

The NCAA rule is slightly different because the defense can possess the ball without the ball becoming dead. In the NCAA, a point-after try is only a dead ball when "it becomes clear the try has failed." In the Fiesta Bowl, the try was blocked, but there was still some possibility that Oregon could have recovered the ball in the end zone for a two-point conversion, or indeed that K-State could have returned the missed kick for a one-point safety by reaching the other end zone. The officials did not declare it dead until the K-State player was tackled in the end zone.

By the way: go look at the Fiesta Bowl replay. The kick was blocked and recovered in the field of play by K-State. The one-point safety is avoided by simply taking a knee.